If it is Exchange, then Outlook will show out the new message when new messages arrived~~~
BTW
u can specify the force transfer and receive time for Exchange and Outlook
On Outlook, ==> Tools ==> Option ==> Mail Setting ==> Transfer and Receive ==> You can see the setup time for transfer and receive of the mail under outlook
MCPD .Net, CCNP Love programming, but not an IT Guy Haha! :D